When Mt Redoubt erupted in 1989/90, we continued operating into Anchorage (daylight only), visually avoiding the plume. This often meant a longer route in, due to the closeness of Mt Redoubt to Anchorage.
If there are any engineers who were around at the time then perhaps they could comment as to whether there was any damage to the aircraft during these times.
The KLM 744 for starters...